Digital watermarks and signatures are known techniques for embedding information in data. Such data typically comprises a digital representation of information such as a sound recording or an image. These techniques are thus of particular significance in the field of media ownership for overcoming media piracy.
The above techniques provide a means of producing a representation of the original information that has unique information stored therein. The unique information can be extracted at a later time for authentication purposes and/or for claiming ownership of the original information. It can also be used to detect if any unauthorised modifications have been made to the original information. However, many such techniques are complex in implementation and may alter the perceptible appearance of original information.
A need exists to provide a relatively simple method and apparatus for image authentication, wherein authentication information is embedded within an image itself, while substantially preserving the perceptible appearance of the original unauthenticated image.